Caption: colour enhanced CT (computed tomography) scan showing the frontal view of a male pelvis. The yellow-green structure is a collapsed urinary bladder. The round purple structure is the prostate gland which is normal. Just below the prostate is a smaller red structure representing the seminal vesicles. When the prostate gland becomes enlarged it typically grows into the base of the urinary bladder. It is for this reason that one of the symptoms of an enlarge prostate gland is difficulty with urination. CT (or CAT) scans are complex types of x-rays which generate cross sectional images like slices in a loaf of bread. The computer can also create images in other views by manipulating the data.